JP5006265B2 - Sterilizer - Google Patents

Description

  The present invention relates to a sterilization apparatus for use in a sterilization method for sterilizing bottles and caps at the time of manufacturing a bottled beverage, for example, using a peracetic acid-based sterilant containing peracetic acid, hydrogen peroxide, and acetic acid.

  A sterilization method and a sterilizer using a peracetic acid-based sterilant are known as chemical solutions used for sterilization of bottles when manufacturing bottled beverages.

  As such a sterilization method, Patent Documents 1 and 2 disclose that a chemical solution is heated to 60 ° C. or higher when the chemical solution is used.

  Patent Document 2 discloses that a chemical tank is kept warm at a temperature close to 60 ° C.

JP 2003-127713 A Japanese Patent Laid-Open No. 2004-210387

  However, the peracetic acid-based sterilant is replenished by adding peracetic acid to the chemical tank because the concentration of peracetic acid decreases due to thermal decomposition when the temperature exceeds a predetermined temperature. For example, as shown in FIG. 2, when the peracetic acid-based sterilant was stored at a predetermined temperature, the concentration after a predetermined time elapsed was measured. Reduced by 20%.

  When peracetic acid is replenished by reducing the concentration of peracetic acid, there is a problem that the management cost of the sterilizing agent is increased and the concentration management of the chemical tank is troublesome.

  Accordingly, an object of the present invention is to provide a sterilization apparatus that can suppress an increase in cost of a peracetic acid-based sterilant and that can easily manage concentration.

  In order to solve the above problem, the invention described in claim 1 sterilizes a resin container for beverages or a resin cap of a container with a peracetic acid-based sterilant containing peracetic acid, hydrogen peroxide, and acetic acid. A sterilizer that contains a peracetic acid-based sterilant, a chemical tank that stores the peracetic acid-based sterilant, a forward pipe that leads the peracetic acid-based sterilant from the chemical liquid tank to the sterilizer, and heating that is provided in the forward pipe to heat the peracetic acid-based sterilant And a return pipe for returning the peracetic acid-based sterilant after use in the sterilizer to the chemical tank, and a cooler for cooling the used peracetic acid-based sterilant is provided in the middle of the return pipe. The sterilizer is characterized in that a heat exchanger is provided between the cooler and the sterilizer to exchange heat with the peracetic acid sterilizing agent in the forward pipe.

The invention described in claim 2 is the invention described in claim 1 , wherein the temperature of the peracetic acid sterilant in the chemical tank is 35 ° C. or less, and the temperature of the peracetic acid sterilant used in the sterilizer is 60. C. to 70.degree. C.

The invention described in claim 3 is characterized in that, in the invention described in claim 2 , the temperature of the peracetic acid-based sterilant in the chemical tank is 25 ° C to 35 ° C.

  As a result of experiments, it was found that peracetic acid was thermally decomposed and the peracetic acid concentration decreased in a peracetic acid-based sterilant when the temperature increased.

  Therefore, according to the present invention, since the used peracetic acid-based sterilant is cooled and stored, the thermal decomposition can be suppressed and the peracetic acid concentration can be prevented from being lowered. The concentration of peracetic acid can be easily managed.

  From the experimental results, the storage temperature of the used peracetic acid-based sterilant is preferably 35 ° C. or lower, more preferably 25 ° C. to 35 ° C.

  When the temperature is 35 ° C. or lower, the concentration can be reduced to 2% to 3% after 60 minutes, and the concentration can be reduced substantially to zero at about 30 ° C.

  On the other hand, when the temperature is lower than 25 ° C., the peracetic acid-based sterilizing agent generally needs to be heated to a sterilization temperature of 60 ° C. to 70 ° C. when used in a sterilizer. There is an inconvenience that the energy required to do this increases.

The peracetic acid sterilant in the sterilizer may be cooled by providing a cooler in the return path between the chemical tank and the sterilizer to cool the peracetic acid sterilant used in the sterilizer .

  If a heat exchanger is installed in the forward path before heating the peracetic acid-based sterilant used in the sterilizer, the heat of the used peracetic acid-based sterilant in the return path is heat-exchanged in the heat exchanger to lower the temperature, and the return path The thermal efficiency when cooling the peracetic acid-based sterilant can be increased.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of a sterilization apparatus according to an embodiment of the present invention, and FIG. 2 shows the results of an experiment in which the relationship between the temperature of a peracetic acid-based sterilant and the concentration of peracetic acid is measured for each elapsed time. FIG. 3 is a graph showing the results of an experiment in which the relationship between the temperature of the peracetic acid-based sterilant and the hydrogen peroxide concentration was measured for each elapsed time.

  First, the configuration of the sterilization apparatus according to the first embodiment will be described with reference to FIG. The sterilizer sterilizes resin bottles and caps in a plastic bottled beverage manufacturing plant, and supplies the chemical solution in the chemical solution tank 3 to the bottle sterilizer 5 and the cap sterilizer 7. Yes.

  The chemical solution is a peracetic acid-based sterilant containing peracetic acid, hydrogen peroxide, and acetic acid, and a stabilizer is mixed as necessary.

  An outward pipe 9 and a return pipe 11 are connected between the chemical liquid tank 3 and the bottle sterilizer 5, and the forward pipe 9 supplies the chemical liquid derived from the chemical liquid tank 3 to the bottle sterilizer 5 for bottle sterilization. The chemical solution used in the machine 5 is returned to the chemical solution tank 3 by the return pipe 11.

  The forward pipe 9 is provided with a pump 13 and a strainer 15 for extracting the chemical liquid from the chemical tank 3, and the chemical liquid that has passed through the strainer 15 is heat-exchanged with the chemical liquid in the return pipe 11 by a heat exchanger (tube heater) 17. Then, it is heated by a steam heater (tube heater) 19 and supplied to the bottle sterilizer 5.

  The return pipe 11 returns the used chemical solution to the chemical tank 3 in the bottle sterilizer 5, supplies the used chemical solution to the heat exchanger 17 by heating to 60 ° C. to 70 ° C. After exchanging heat with the chemical solution, it is cooled by a cooler (tube cooler) 21 and returned to the chemical solution tank 3 via a strainer 23.

  The forward pipe 9 and the backward pipe 11 between the chemical liquid tank 3 and the cap sterilizer 7 have the same configuration as that of the bottle sterilizer 5 described above, and a strainer 15, a heat exchanger 17, steam are added to the forward pipe 9. Heating 19 is provided, the return pipe 11 passes through the heat exchanger 17, and a cooler 21 and a strainer 23 are provided downstream of the heat exchanger 17.

  Next, the operation and effect of the sterilizer will be described. The chemical solution tank 3 stores a peracetic acid-based sterilant (chemical solution) held at about 30 ° C. The chemical solution derived from the chemical solution tank is exchanged with the chemical solution in the return pipe 11 by the heat exchanger 17. Heated and heated to 60 ° C. to 70 ° C. by the steam heater 19. And in the bottle sterilizer 5, a bottle is sterilized with the chemical | medical solution heated at 60 to 70 degreeC. The reason why the chemical temperature is set to 60 ° C. to 70 ° C. in the bottle sterilizer 5 is to increase the sterilization effect.

  The chemical solution after being used in the bottle sterilizer 5 is heat-exchanged with the chemical solution in the forward path 9 by the heat exchanger 17, cooled to about 30 ° C. by the cooler 21, and then returned to the chemical solution tank 3.

  That is, in the present embodiment, the chemical solution in the chemical solution tank 3 is stored at about 30 ° C. and heated to 60 ° C. to 70 ° C. during use.

  In the present embodiment, since the storage temperature in the chemical tank 3 is 30 ° C., it is possible to prevent a decrease in peracetic acid concentration due to thermal decomposition.

  Here, since it experimented about the relationship between the storage temperature and density | concentration of a peracetic acid type sterilant, the result is demonstrated.

  In the experiment, the peracetic acid concentration at each elapsed time when a peracetic acid-based sterilant having a predetermined concentration was stored at various temperatures was measured. The result is shown in FIG. In FIG. 2, o is the storage temperature of 30 ° C., x is 40 ° C., and □ and ◇ are about 68 ° C. The reason why two data are taken with □ and ◇ at 68 ° C is that measurement errors are likely to occur at high temperatures. The vertical axis is concentration and the horizontal axis is time.

  As is apparent from FIG. 2, when the storage temperature was about 30 ° C., the peracetic acid concentration did not decrease significantly, and after 60 minutes, substantially the same concentration could be maintained. On the other hand, when the storage temperature was about 40 ° C., a concentration decrease of about 4% was observed after 60 minutes, and at 68 ° C., the concentration decrease was about 20%.

  Therefore, in order to prevent a decrease in concentration, the storage temperature of the chemical solution is preferably about 30 ° C., preferably about 25 ° C. to 35 ° C. In this temperature range, it is clear that the peracetic acid concentration can be prevented from decreasing due to thermal decomposition.

  When the concentration of peracetic acid decreases, the concentration of hydrogen peroxide increases because peracetic acid has an equilibrium of the following formula (1). However, when hydrogen peroxide increases, the oxidation of metal piping and the chemistry with organic matter There is a problem that synthetic substances are increased by reaction.

(Chemical 1)
CH ₃ COOOH (peracetic acid) + H ₂ O⇔CH ₃ COOH + H ₂ O ₂ (1)
Here, an experiment was conducted in which the relationship between the temperature of the peracetic acid sterilant and the hydrogen peroxide concentration was measured every elapsed time, and the results are shown in FIG.

  The measurement of the hydrogen peroxide concentration shown in FIG. 3 was performed for the peracetic acid-based sterilant used in the experiment shown in FIG. The symbols used in the graph of FIG. 3 are the same temperature symbols as in FIG.

  As is apparent from FIG. 3, the hydrogen peroxide concentration hardly changes even after 60 minutes when the storage temperature is 30 ° C., but about 5% when the storage temperature is 68 ° C. When the temperature was 40 ° C., it increased by about 2%.

  As is apparent from the measurement of the hydrogen peroxide concentration, when the storage temperature was 30 ° C., there was almost no decrease in the concentration due to thermal decomposition of peracetic acid because the hydrogen peroxide concentration did not change. it is obvious.

Next, other embodiments will be described as reference examples not included in the present invention. In the embodiments described below, the same portions as those in the first embodiment described above are the same. By attaching reference numerals, detailed description of the portions is omitted, and points that are mainly different from the first embodiment will be described.

  FIG. 4 shows a sterilizer according to the second embodiment. In the second embodiment, the chemical liquid tank 3 is provided with the cooling jacket 31, and the chemical liquid tank 3 is cooled by the cooling jacket 31, and the cooler 21 is not provided in the return path 11. Different from the embodiment.

  The cooling jacket 31 is provided around the chemical tank 3 and cools the chemical tank 3 with a refrigerant. As the refrigerant, industrial water, groundwater, or the like can be used.

  In the second embodiment, the same operational effects as those of the first embodiment can be obtained.

It is a block diagram which shows the structure of the sterilizer which concerns on embodiment of this invention. It is a graph which shows the result of the experiment which measured the relationship between the temperature of a peracetic acid type sterilant, and a peracetic acid density | concentration for every elapsed time. It is a graph which shows the result of the experiment which measured the relationship between the temperature of a peracetic-acid type | system | group sterilant, and hydrogen peroxide concentration for every elapsed time. It is a block diagram which shows the structure of the sterilizer which concerns on 2nd Embodiment as a reference example which is not included in this invention.

3 Chemical liquid tank 5 Bottle sterilizer 7 Cap sterilizer 17 Heat exchanger 19 Heater 21 Cooler

Claims (3)

  A sterilizer for sterilizing a resin container for beverages or a resin cap of a container with a peracetic acid-based sterilant containing peracetic acid, hydrogen peroxide, and acetic acid, a chemical tank containing the peracetic acid-based sterilant, Outgoing pipe that leads the peracetic acid-based sterilant from the chemical tank to the sterilizer, a heater that is installed in the outgoing pipe to heat the peracetic acid-based sterilant, and the peracetic acid-based sterilant that is used in the sterilizer is stored in the chemical tank And a cooler for cooling the used peracetic acid-based sterilant is provided in the middle of the return pipe, and the return pipe has a peracetic acid system for the forward pipe between the cooler and the sterilizer. A sterilizer provided with a heat exchanger for exchanging heat with a sterilant. The sterilizer according to claim 1 , wherein the temperature of the peracetic acid sterilant in the chemical tank is 35 ° C or lower, and the temperature of the peracetic acid sterilant used in the sterilizer is 60 to 70 ° C. The temperature of the peracetic acid type sterilant in a chemical | medical solution tank is 25 to 35 degreeC, The sterilizer of Claim 2 characterized by the above-mentioned.

Images